#ifndef SPHERE_H
#define SPHERE_H

#include "common/rtweekend.h"
#include "hittable.h"

class sphere: public hittable  {
public:
  sphere() {}
  sphere(vec3 cen, float r, material *m)
    : center(cen), radius(r), mat_ptr(m)  {};
  virtual bool hit(const ray& r, float tmin, float tmax, hit_record& rec) const;
  vec3 center;
  float radius;
  material *mat_ptr;
};

bool sphere::hit(const ray& r, float t_min, float t_max, hit_record& rec) const {
  vec3 oc = r.origin() - center;
  // with canceled factors of two removed from quadratic solution
  float a = dot(r.direction(), r.direction());
  float b = dot(oc, r.direction());
  float c = dot(oc, oc) - radius*radius;
  float discriminant = b*b - a*c;
  if (discriminant > 0) {
    float temp = (-b - sqrt(discriminant))/a;
    if (temp < t_max && temp > t_min) {
      rec.t = temp;
      rec.p = r.point_at_parameter(rec.t);
      rec.normal = (rec.p - center) / radius;
      rec.mat_ptr = mat_ptr;
      return true;
    }
    temp = (-b + sqrt(discriminant)) / a;
    if (temp < t_max && temp > t_min) {
      rec.t = temp;
      rec.p = r.point_at_parameter(rec.t);
      rec.normal = (rec.p - center) / radius;
      rec.mat_ptr = mat_ptr;
      return true;
    }
  }
  return false;
}


#endif
